The objective of this project is to develop and evaluate an MRI-guided robotic system to enable novel, transforamenal ablation of the hippocampus to treat epilepsy. This work is motivated by the high prevalence of and severe disability caused by epilepsy. Epilepsy has a prevalence of 1 in 100 to 200 persons globally, with 20-40% of the patient population being unresponsive to drug therapy and at risk for sudden unexplained death in epilepsy (SUDEP) at rates estimated to be as high as 1% per patient per year [1-5]. While hippocampectomy is known to permanently cure epilepsy at a high rate (70-80%), this surgery is vastly underutilized, due to the invasiveness and perceived morbidity of this open brain procedure [4,6-7]. Our new steerable needle system will provide a percutaneous treatment by deploying through a straight outer cannula, which is manually inserted beneath the cheek skin and docked to the foramen ovale, a small natural opening in the skull base. A helically-curved, shape-memory alloy needle, actuated at its distal end by a precision pneumatic robot, will maneuver a radiofrequency ablation electrode from the foramen ovale to and through the hippocampus from head to tail. Magnetic resonance imaging and thermometry will guide the needle along the planned path, and monitor the delivery of thermal ablative therapy. The aims of this project involve: 1) modifying and evaluating existing robot and steerable ablation electrode hardware, 2) developing MR imaging protocols for visualization and temperature measurement of tissue adjacent to the ablation electrode, and 3) demonstrating the system's effectiveness in needle steering and conformal ablations, using mock procedures in ex-vivo phantoms under full MRI guidance, with confirmatory histology. A multidisciplinary team of investigators will carry out these aims by combining expertise in epilepsy surgery (Co-I Neimat), mechanical design and precision control of robotic systems (PI Barth), design and control of concentric tube steerable needles (PI Webster), and MRI and thermometry for guided interventions and thermotherapy (Co-I Grissom). The endpoint and metric of success for this R21 project will be the demonstration of a controlled and precise robot-enabled ablation through the foramen ovale in a mock procedure using MR guidance. This work will pave the way for a future R01-funded project involving cadaveric and animal studies.